Bug 1855820

+++ This bug was initially created as a clone of Bug #1855818 +++

Description of problem:
When I access a TriggerTemplate by clicking on the link to it in the Pipeline Details screen, I can then select the option to Edit the TriggerTemplate. This redirects me to a YAML editor but I can't save my changes.

Prerequisites (if any, like setup, operators/versions):
Pipelines Operator 1.0.1, OpenShift 4.5.0-rc.4

Steps to Reproduce
1. From the Pipelines list in the Developer console, click on a Pipeline that has a Trigger
2. Click on the TriggerTemplate
3. In the TriggerTemplate Details screen, select "Edit Trigger Template" from the dropdown menu
4. The YAML editor opens up but in read-only mode

Actual results:
The editor opens up in read-only mode. I can't do changes and there is no save button.

Expected results:
I should be able to edit the Trigger Template. If this screen is meant to be read-only, then perhaps the wording should change from "Edit Trigger Template" to "View Trigger Template YAML file"

Reproducibility (Always/Intermittent/Only Once):
Always

Build Details:
Additional info:
We should make all trigger resources editable at the same time:

Event Listener
Cluster Trigger Binding
Trigger Binding
(and) Trigger Template